fetal liver (1)

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Rom J Morphol Embryol2013, 54(X):YZ

OORIGINALRIGINALPAPERPAPER

Fetal liver development aspects

1)F. Grosu, Anca Roca2), Liliana Coldea3), A. L. Stupariu4), Mariana Sabu!)

1)"epart#ent o$ Morp%olo&'

,,Lucian (la&a *ni+ersit', Sibiu

2)"epart#ent o$ Sur&er'

*ni+ersit' o$ Medicine and %ar#ac' o$ -r&u Mure

3)"epart#ent o$ /ursin&,,Lucian (la&a *ni+ersit',Sibiu

4)"epar#ent o$ 0p%t%al#olo&'

#er&enc' Clinical Count' ospital Sibiu

!)

"epar#ent o$ "ental #edicine,,Lucian (la&a *ni+ersit',Sibiu

Abstract

-%e li+er %olds $or a s%ort period o$ ti#e in its onto&enetic de+elop#ent t%e #ost i#portant part in%e#atopoeisis.

n order to acco##odate t%is transient $uction, t%at #etaints its latent caracteristic $or li$e, t%e li+er blast cellspresent special #orp%olo&ic and ar%itectural caracteristics.

Considerin& %e#atopoiesis t%e #ain li+er $uction e described t%e blast cells it% t%ere #esoder#al andendoder#al ori&in $or t%e $oloed onto&entic #o#ent.

Keywords: %epatoblasts, %e#atopoesis, #acrop%a&es, #e5enc%i#al cell

Introduction-%e li+er de+elops in t%e be&innin& as t%e anterior all o$ t%e pri#iti+e duodenu#. nitiall' appears t%e %epatic

di+erticulu# t%at &ros $ast to t%e trans+erse septu# #esenc%'#e.

-%e trans+erse septu# is $or#ed $ro# #esenc%'#e $ound betee# t%e +entral #eso&aster la#ina and appearsin t%e be&innin& in t%e e#br'o cer+icalr re&ion $ro# %ere descends it% t%e %eart 61).

-%e li+er bud di$$erentiate t%e %epato blastic cords cells $ro# ic% t%e li+er parenc%'#a de+elops and t%eepit%eliu# intra%epatic &a$i ducts.

-%e %epatoblasts appear as disordered cell cords, t%at $or# a #es% netor7 in ic% e $ind residual trans+erseseptu# #esenc%'#a. -%is %as %e#ato&enenous properties and &enerates blood islands, $ro# ic% t%e li+er capillar'

netor7 de+elops.Also $ro# t%e trans+erse septu# #esenc%'#e t%e li+er #acrop%a&es are $or#ed and t%e stro#al con8ucti+e tissue

62).-%e li+er %e#ato&enous $uction %as a #a8or i#portance in t%e $etal period, t%an it descreseas &raduall', at birt%

re#ain& onl' a couple o$ islands in t%e li+er parenc%'#e.-%e li+ers %e#ato&enous potential is 7ept $or li$e, but ill onl' #ani$est is e9ceptional situations.

Folloin& t%e ori&inatin& e#briolo&ical structures e anted to %i&%li&%t li+er cells $or t%e #iece $etuses it% t%e&estationl a&e corespondin& to t%e t%ird tri#ester o$ pre&nac'.

Materials and methods

n order to %i&%li&%t t%e structures o$ t%e $etal li+er e %a+e used se+eral parasa&ital sections #ade on #ice

$etuses it% t%e ce$alo:caudal si5e o$ 33##, ic% coresponds to t%e $oloed onto&enetic #o#ent, t%e last period o$

pre&nanc'.;e %a+e used 1< bod' $etuses t%at %a+e been processed b' %istolo&ical tec%ni=ues. ;e #ade parasa&ital section

t%rou& t%e $etuses bod's, e colored t%e# it% %e#ato9'lin eu5ina 6), and t%an t%e' ere e9a#ined andp%oto&rap%aed under a #icroscope.

Results;e %a+e $olloed t%e structural co#ponents o$ t%e $etal li+er it% its di$$erent e#brilo&ical ori&ins, t%ose t%at

ca#e $ro# t%e ectoder# ill $or# t%e $inal li+er cells, and t%ose t%at ca#e $or t%e #esoder# ill $or# t%e stro#al

ISSN (print) 12200522 ISSN (on-line) 20668279

R J M ERomanian Journal of

Morphology & Embryology

http://www.rjme.ro/


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%e#atopoetic cells.-%e $etal polilobulat li+er, %olds si#ilar relations%ip it% t%e one 7non $or adults.

Discussions

0n parasa&ital section e %a+e obser+ed t%e $oloin& relations> %i&%er %as inter#ediate diap%&ra# contact it%t%e %eart and lun&s, loer %as contact it% t%e sto#ac% and 8e8uno:ileal loops. osterior relation is it% t%e

diap%raatic pillar, descendin& aorta and esop%a&us 6t%ose s%on on t%e presented i#a&e). Anterior %as contact

it% t%e bod's all.

Fi&ure 1

-%e li+er beein& t%e #ost i#portant or&an o$ %e#atopoiesis &enerates a propitius en+iron#ent $or t%e

de+elop#ent o$ %e#ato&enous lines $or a certain onto&enetic #o#ent. -%e li+er cells t%e#sel+es ill be

responsabble $or t%e induction o$ %e#ato&enous $uction 63).

-%e li+er cells can %a+e an endoder#al ori&in 6%epatoblast cells, intra%epatic &a$i ducts cells) and #esoder#alori&in 6#esenc%i#al cells, reticular cells, stro#al cells, $ibroblasts, #'oblast, s#oot% +ascular #uscle $iber and

endotelial di$erentiated cells). -%e %e#ato&enous $uction &enerates t%e %e#apoietic lines.-%e %epatoblasts, in t%e earl' de+elop#ent sta&es %a+e a bopotent c%aracter 64) so#e o$ t%e# e+ol+in& in

%epatoc'tes and ot%ers in c%olan&ioc'tes. epatoblast can be indenti$ied as bi& cells, it% basop%ilic c'toplas#,scratc%', it% eucr%o#a nucleus, arran&ed in irre&ular cords.

Fi&ure 2

-%e %epataoblasts irre&ular pro+ision is obious b' t%e lac7 o$ c'toarc%itectonic di$$erntations speci$ic to t%e

li+er, basicl' $or t%e $oloed onto&enetic #o#ent e couldnt identi$' t%e li+er speci$ic lobules, t%e li+erar%itecture is disodered it% +eins t%at ill beco#e central lobular it% c%aotic disposal 6Fi&ure 2).

-%e %epatablasts directl' inter$ere it% t%e %epatopoetic cells. epatocic:li7e cells see# to pla' ani#portant part in %e#aptopiesis interactin& directl' it% er't%roblasts and probabl' t%e' induce er't%ropoiesis

t%rou&% en5'#es suc% as er't%ropoietin.n a si#ilar a' %epatoblasts are in+ol+ed in t%e di$erentation o$ #e&a7ar'oc'tes t%rou&% t%ro#bopoietin li7el'

secretion 6Fi&ure 3).

Fi&ure 3

-%e #e&a7ar'oc'te 6!) can be indenti$ied b' t%e $olloin& $eatures, t%e' are lar&e cells it% acidop%ile c'toplas#a,

it% t%e core #ore ore less seentated acordin& to t%e c%oosen onto&enetic #o#ent and acti+it' 6 Fi&ure 3).

Fi&ure 4

Macrop%a&es are di$$erentiated in to bi& cell classes. -%e $irst are t%e er't%roblast islands #acrop%a&es. n t%e

acti+e sta&e o$ %e#atopoiesis t%e' #i&rate in t%e li+er parenc%'#a and participate in t%e $or#in& o$ t%e er'troblastislands, $or#ed $ro# a central #acrop%a&e and etrioblast in di$$erent $or#in& sta&es, situated in perip%er', cells t%at

%a+e #orp%olo&ical l'#p%oc'te c%aracteristic 6?,@).-%e second #acrop%a&es class is represented b' cells t%at ill di$erenatiate into up$$er cells, t%at are in

a closser relantions%ip it% t%e sinusoidal capillaries. -%e' can ori&inate $ro# t%e blood ste# cell, but t%e' can alsoori&nate directl' $ro# t%e #esenc%i#al cells 6B), -%eir role in %e#atopoiesis is to p%a&oc'ti5e t%e e9luded core o$

t%e er'troblast 6,1


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i#portant role on #ieloid separation.61@).

Fi&ure ?

-%e plain #uscular cells, at t%e adult are $ound onl' on #ediu# tunic o$ t%e %epatic arter' and its branc%es. n t%eli+er t%e #ieloblasts are locali5ed around t%e +eins and are i#plied on %e#atopoesis 61B). -%ese cells t%rou&% t%eir

contractil c%aracteristics can controll t%e %e#atopoetic cells #i&ration #odi$'in& t%e per#eabilit' o$ interstitial

areas beteen t%e endoteliocite cells.Dascular endoteliu# %as a di$$erent structure dependin& on its position and #or$olo&ical role, can be $or#ed b' acontinued endotelial stratu# at t%e le+el o$ porte +eins, or a $enestrat epiteliu# at t%e le+el o$ centrolobular +eins.

61). -ied to t%e %e#atopoesis are t%e sinusoid capillar' t%at are e9tre#l' per#eable $or t%e $i&urate san&+inele#ents prodused inside t%e li+er.

Fi&ure @

-%e stro#al #e5enc%i#al cells, are #ulti$unctional cells %ic% can be di$$erentiated practicall' on e+er' t'pe o$

cells it% #e5enc%i#al ori&in. -%e' %a+e an ori&in on t%e #e5enc%i# o$ t%e trans+ers septu# but can be also onso#atic #e5enc%i# para9ial undi+ided. -%e presence o$ t%ese cells in t%e li+er is tied onl' b' t%e %e#atopoetic

acti+it' 62@. ". Li, G. . ;an&, I. F. Liu, . J. S%i, . I%an&, and I. L. (ai, Macrop%a&e:associated er't%ropoiesis andl'#p%oc'topoiesis in #ouse $etal li+er> ultrastructural and S anal'sis,E Cell (iolo&' nternational, +ol. 2B, no. ?,

pp. 4!@H4?1, 2 e+idence o$ transdi$$erentiation $ro# epit%elial to #esenc%'#al p%enot'pe,E

istoc%e#istr' and Cell (iolo&', +ol. 11B, no. 2, pp. 12@H13?, 2


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li+er,E Co#parati+e epatolo&', +ol. B, article !, 2


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